| 1. |
- Ahlstrand, Erik, 1974-, et al.
(author)
-
Visual scoring of chest CT at hospital admission predicts hospitalization time and intensive care admission in Covid-19
- 2021
-
In: Infectious Diseases. - : Taylor & Francis. - 2374-4235 .- 2374-4243. ; 53:8, s. 622-632
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Chest CT is prognostic in Covid-19 but there is a lack of consensus on how to report the CT findings. A chest CT scoring system, ÖCoS, was implemented in clinical routine on 1 April 2020, in Örebro Region, Sweden. The ÖCoS-severity score measures the extent of lung involvement. The objective of the study was to evaluate the ÖCoS scores as predictors of the clinical course of Covid-19.METHODS: Population based study including data from all hospitalized patients with Covid-19 in Örebro Region during March to July 2020. We evaluated the correlations between CT scores at the time of admission to hospital and intensive care in relation to hospital and intensive care length of stay (LoS), intensive care admission and death. C-reactive protein and lymphocyte count were included as covariates in multivariate regression analyses.RESULTS: In 381 included patients, the ÖCoS-severity score at admission closely correlated to hospital length of stay, and intensive care admission or death. At admission to intensive care, the ÖCoS-severity score correlated with intensive care length of stay. The ÖCoS-severity score was superior to basic inflammatory biomarkers in predicting clinical outcomes.CONCLUSION: Chest CT visual scoring at admission to hospital predicted the clinical course of Covid-19 pneumonia.
|
|
| 2. |
- Alshamari, Muhammed, 1975-, et al.
(author)
-
Impact of iterative reconstruction on image quality of low-dose CT of the lumbar spine
- 2017
-
In: Acta Radiologica. - London : Sage Publications. - 0284-1851 .- 1600-0455. ; 58:6, s. 702-709
-
Journal article (peer-reviewed)abstract
- Background: Iterative reconstruction (IR) is a recent reconstruction algorithm for computed tomography (CT) that can be used instead of the standard algorithm, filtered back projection (FBP), to reduce radiation dose and/or improve image quality.Purpose: To evaluate and compare the image quality of low-dose CT of the lumbar spine reconstructed with IR to conventional FBP, without further reduction of radiation dose.Material and Methods: Low-dose CT on 55 patients was performed on a Siemens scanner using 120 kV tube voltage, 30 reference mAs, and automatic dose modulation. From raw CT data, lumbar spine CT images were reconstructed with a medium filter (B41f) using FBP and four levels of IR (levels 2-5). Five reviewers scored all images on seven image quality criteria according to the European guidelines on quality criteria for CT, using a five-grade scale. A side-by-side comparison was also performed.Results: There was significant improvement in image quality for IR (levels 2-4) compared to FBP. According to visual grading regression, odds ratios of all criteria with 95% confidence intervals for IR2, IR3, IR4, and IR5 were: 1.59 (1.39-1.83), 1.74 (1.51-1.99), 1.68 (1.46-1.93), and 1.08 (0.94-1.23), respectively. In the side-by-side comparison of all reconstructions, images with IR (levels 2-4) received the highest scores. The mean overall CTDIvol was 1.70 mGy (SD 0.46; range, 1.01-3.83 mGy). Image noise decreased in a linear fashion with increased strength of IR.Conclusion: Iterative reconstruction at levels 2, 3, and 4 improves image quality of low-dose CT of the lumbar spine compared to FPB.
|
|
| 3. |
|
|
| 4. |
- Alshamari, Muhammed, 1975-, et al.
(author)
-
Low dose CT of the lumbar spine compared with radiography : a study on image quality with implications for clinical practice
- 2016
-
In: Acta Radiologica. - London, United Kingdom : Sage Publications. - 0284-1851 .- 1600-0455. ; 57:5, s. 602-611
-
Journal article (peer-reviewed)abstract
- Background: Lumbar spine radiography is often performed instead of CT for radiation dose concerns.Purpose: To compare image quality and diagnostic information from low dose lumbar spine CT at an effective dose of about 1 mSv with lumbar spine radiography.Material and Methods: Fifty-one patients were examined by both methods. Five reviewers scored all examinations on eight image quality criteria using a five-graded scale and also assessed three common pathologic changes.Results: Low dose CT scored better than radiography on the following: sharp reproduction of disc profile and vertebral end-plates (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.3-2.5), intervertebral foramina and pedicles (OR, 4.3; 95% CI, 3.1-5.9), intervertebral joints (OR, 139; 95% CI, 59-326), spinous and transverse processes (OR, 7.0; 95% CI, 4.3-11.2), sacro-iliac joints (OR, 4.2; 95% CI, 3.2-5.7), reproduction of the adjacent soft tissues (OR, 2.9; 95% CI, 2.1-4.0), and absence of any obscuring superimposed gastrointestinal gas and contents (OR, 188; 95% CI, 66-539). Radiography scored better on sharp reproduction of cortical and trabecular bone (OR, 0.3; 95% CI, 0.2-0.4). The reviewers visualized disk degeneration, spondylosis/diffuse idiopathic skeletal hyperostosis (DISH) and intervertebral joint osteoarthritis more clearly and were more certain with low dose CT. Mean time to review low dose CT was 204 s (95% CI, 194-214 s.), radiography 152 s (95% CI, 146-158 s.). The effective dose for low dose CT was 1.0-1.1 mSv, for radiography 0.7 mSv.Conclusion: Low dose lumbar spine CT at about 1 mSv has superior image quality to lumbar spine radiography with more anatomical and diagnostic information.
|
|
| 5. |
- Andersson, Karin M., 1989-, et al.
(author)
-
Visual grading evaluation of commercially available metal artefact reduction techniques in hip prosthesis computed tomography
- 2016
-
In: British Journal of Radiology. - London, United Kingdom : British Institute of Radiology. - 0007-1285 .- 1748-880X. ; 89:1063
-
Journal article (peer-reviewed)abstract
- Objectives: To evaluate metal artefact reduction (MAR) techniques from four computed tomography (CT) vendors in hip prosthesis imaging.Methods: Bilateral hip prosthesis phantom images, obtained by using MAR algorithms for single energy CT data or dual energy CT (DECT) data and by monoenergetic reconstructions of DECT data, were visually graded by five radiologists using ten image quality criteria. Comparisons between the MAR images and a reference image were performed for each scanner separately. Ordinal probit regression analysis was used.Results: The MAR algorithms in general improved the image quality based on the majority of the criteria (up to between 8/10 and 10/10) with a statistically improvement in overall image quality (P<0.001). However, degradation of image quality, such as new artefacts, was seen in some cases. A few monoenergetic reconstruction series improved the image quality (P<0.004) for one of the DECT scanners, but it was only improved for some of the criteria (up to 5/10). Monoenergetic reconstructions resulted in worse image quality for the majority of the criteria (up to 7/10) for the other DECT scanner.Conclusions: The MAR algorithms improved the image quality of the hip prosthesis CT images. However, since additional artefacts and degradation of image quality were seen in some cases, all algorithms should be carefully evaluated for every clinical situation. Monoenergetic reconstructions were in general concluded to be insufficient for reducing metal artifacts. Advances in knowledge: Qualitative evaluation of the usefulness of several MAR techniques from different vendors in CT imaging of hip prosthesis.
|
|
| 6. |
- Dreifaldt, Mats, 1959-, et al.
(author)
-
Pedicled versus skeletonized internal thoracic artery grafts : a randomized trial
- 2021
-
In: Asian cardiovascular & thoracic annals. - : Medikaru Toribyun. - 1816-5370 .- 0218-4923. ; 29:6, s. 490-497
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: Concerns have been raised regarding whether skeletonization of the internal thoracic artery could damage the graft and thereby reduces its patency. The objective of this study was to compare patency rates at mid- and long-term follow-up between pedicled and skeletonized left internal thoracic artery grafts.METHODS: This randomized controlled trial included 109 patients undergoing coronary artery bypass surgery. The patients were assigned to receive either one pedicled or one skeletonized left internal thoracic artery graft to the left anterior descending artery. Follow-up was performed at 3 years with conventional angiography, and at 8 years with computed tomography angiography. Differences between patency rates were analyzed with Fisher's exact test and a generalized linear model.RESULTS: The patency rates for pedicled and skeletonized left internal thoracic artery grafts were 46/48 (95.8%) versus 47/52 (90.4%), p = 0.44 at 3 years, and 40/43 (93.0%) versus 37/41 (90.2%), p = 0.71 at 8 years, respectively. The difference in patency rates for pedicled and skeletonized grafts was 5.4% (95% confidence interval: -4.2-14.5) at 3 years and 2.8% (95% confidence interval: -9.9-14.1) at 8 years. All failed grafts, except for one with a localized stenosis, were anastomosed to native coronary arteries with a stenosis less than 70%. Three patients suffered sternal wound infections (two in the pedicled group, one in the skeletonized group).CONCLUSIONS: The skeletonization technique can be used without jeopardizing the patency of the left internal thoracic artery. The most important factor in graft failure was target artery stenosis below 70%.
|
|
| 7. |
- Dreifaldt, Mats, 1959-, et al.
(author)
-
The no-touch saphenous vein is an excellent alternative conduit to the radial artery 8 years after coronary artery bypass grafting : A randomized trial
- 2021
-
In: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier. - 0022-5223 .- 1097-685X. ; 161:2, s. 624-630
-
Journal article (peer-reviewed)abstract
- Background: In 2004, a prospective randomized trial demonstrated that after 3 years, saphenous veins (SVs) harvested with a no touch (NT) technique had a greater patency than radial grafts for coronary bypass surgery. Here we report the 8-year follow-up data of this trial.Methods: The trial included 108 patients undergoing coronary artery bypass grafting (CABG). Each patient was assigned to receive 1 NT SV and 1 radial artery (RA) graft to either the left or right coronary territory to complement the left internal thoracic artery (LITA). Sequential grafting was common, so overall graft patency as well as the patency of each anastomosis were assessed.Results: Angiography was performed in 84 patients (78%) at mean of 97 months postoperatively. Graft patency were high and similar for both NT and RA: 86% for NT versus 79% for RA (P = .22). The patency of coronary anastomoses was significantly higher with the NT SV grafts (91% vs 81%; P = .046). The NT grafts also had excellent patency in coronary arteries with <90% stenosis (93% patency) and in coronary arteries of small diameter (87% patency) or with mild calcification (88% patency). Patency for the LITA was 92%.Conclusions: NT SV grafts have excellent patency similar to that of RA grafts after 8 years. In addition, NT SV grafts can be used in situations that are not ideal for RA grafts.
|
|
| 8. |
- Ingberg, Edvin, 1988-, et al.
(author)
-
RT-PCR cycle threshold value in combination with visual scoring of chest computed tomography at hospital admission predicts outcome in COVID-19
- 2022
-
In: Infectious Diseases. - : Taylor & Francis. - 2374-4235 .- 2374-4243. ; 54:6, s. 431-440
-
Journal article (peer-reviewed)abstract
- BACKGROUND: COVID-19 has a most variable prognosis. Several risk factors for an unfavourable outcome have been identified including extensive lung involvement on chest CT and high viral load estimated by RT-PCR cycle threshold (Ct) values. We investigated Ct value for outcome prediction, relation between Ct value and extent of lung involvement on chest CT and the combination of Ct value and chest CT lung involvement to predict outcome in COVID-19.METHODS: Population-based retrospective study on all patients (n = 286) hospitalised for COVID-19 in Örebro Region, Sweden, between 1 March and 31 August 2020. Nasopharyngeal samples and chest CT at hospital admission were evaluated in relation to outcome of COVID-19.RESULTS: Both Ct value and chest CT lung involvement were independently associated with risk for ICU admission or death. Lung involvement was superior as a single parameter, but addition of Ct value increased the prediction performance. Ct value was especially useful to identify patients with high risk for severe disease despite limited lung involvement.CONCLUSIONS: The addition of RT-PCR Ct value to the assessment of lung involvement on chest CT adds valuable prognostic information in COVID-19. We believe that this information can be used to support clinical decision-making when managing COVID-19 patients.
|
|
| 9. |
- Lidén, Mats, 1976-, et al.
(author)
-
Two- and three-dimensional CT measurements of urinary calculi length and width : a comparative study
- 2015
-
In: Acta Radiologica. - : Sage Publications. - 0284-1851 .- 1600-0455. ; 56:4, s. 487-492
-
Journal article (peer-reviewed)abstract
- Background: The standard imaging procedure for a patient presenting with renal colic is unenhanced computed tomography (CT). The CT measured size has a close correlation to the estimated prognosis for spontaneous passage of a ureteral calculus. Size estimations of urinary calculi in CT images are still based on two-dimensional (2D) reformats.Purpose: To develop and validate a calculus oriented three-dimensional (3D) method for measuring the length and width of urinary calculi and to compare the calculus oriented measurements of the length and width with corresponding 2D measurements obtained in axial and coronal reformats.Material and Methods: Fifty unenhanced CT examinations demonstrating urinary calculi were included. A 3D symmetric segmentation algorithm was validated against reader size estimations. The calculus oriented size from the segmentation was then compared to the estimated size in axial and coronal 2D reformats.Results: The validation showed 0.1 +/- 0.7mm agreement against reference measure. There was a 0.4mm median bias for 3D estimated calculus length compared to 2D (P < 0.001), but no significant bias for 3D width compared to 2D.Conclusion: The length of a calculus in axial and coronal reformats becomes underestimated compared to 3D if its orientation is not aligned to the image planes. Future studies aiming to correlate calculus size with patient outcome should use a calculus oriented size estimation.
|
|
| 10. |
|
|
| 11. |
- Alobeidi, Hanan, et al.
(author)
-
Minimizing contrast media dose in CT pulmonary angiography with high-pitch technique
- 2020
-
In: British Journal of Radiology. - : John Wiley & Sons. - 0007-1285 .- 1748-880X. ; 93:1111
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: To perform CT pulmonary angiography (CTPA) using a minimal amount of iodinated contrast media.METHODS: 47 patients (25 females) with mean age 69 years (range 41-82 years) referred for contrast-enhanced chest CT were prospectively included in this Phase IV clinical drug trial. All participants underwent a study specific CTPA in addition to the chest CT. The participants received 80 mg I/kg body weight Iohexol contrast media using a preparatory saline bolus, a dual flow contrast/saline bolus and a saline flush, and a scanner protocol with 80 kVp dual source high-pitch mode. Three readers independently assessed the image quality on the 3-point scale non-diagnostic, adequate or good-excellent image quality. Additionally, the pulmonary arterial contrast opacification was measured.RESULTS: On average, the patients received 16.8 ml Iohexol 350 mg I/mL (range 12-20 ml). Mean patient weight was 71 kg (range 50-85 kg). Identically for all readers, pulmonary embolism (PE) was detected in 1/47 participants. The median number of examinations visually scored concerning pulmonary embolism as good-excellent was 47/47 (range 44-47); adequate 0/47 (0-3) and non-diagnostic 0/47 (range 0-0). The proportion adequate or better examinations was for all readers 47/47, 100% [95% confidence interval 92-100%]. The mean attenuation ± standard deviation in the pulmonary trunk was 325 ± 72 Hounsfield unit (range 165-531 Hounsfield unit).CONCLUSIONS: Diagnostic CTPA with 17 ml contrast media is possible in non-obese patients using low kVp, high pitch and carefully designed contrast media administration.ADVANCES IN KNOWLEDGE: By combining several procedures in a CTPA protocol, the contrast media dose can be minimized.
|
|
| 12. |
- Arbeus, Mikael, et al.
(author)
-
Five-year patency for the no-touch saphenous vein and the left internal thoracic artery in on- and off-pump coronary artery bypass grafting
- 2021
-
In: Journal of cardiac surgery. - : Wiley-Blackwell Publishing Inc.. - 0886-0440 .- 1540-8191. ; 36:10, s. 3702-3708
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Randomized trials show high long-term patency for no-touch saphenous vein grafts in coronary artery bypass grafting. The patency rate in off-pump coronary bypass surgery for these grafts has not been investigated. Our center participated in the CORONARY randomized trial, NCT00463294. This is a study aimed to assess the patency of no-touch saphenous veins in on- versus off-pump coronary bypass surgery at five-year follow-up.METHODS: Fifty-six patients were included. Forty of 49 patients, alive at 5 years, participated in this follow-up. There were 21 and 19 patients in the on- and off-pump groups respectively. No-touch saphenous veins were used to bypass all targets and in some cases the left anterior descending artery. Graft patency according to distal anastomosis was evaluated with computed tomography angiography.RESULTS: The five-year patency rate was 123/139 (88.5%). The patency for the no-touch vein grafts was 57/64 (89.1%) in the on-pump versus 37/45 (82.2%) in the off-pump group. All left internal thoracic arteries except for one, 29/30 (96.6%), were patent. All vein grafts used to bypass the left anterior descending and the diagonal arteries were patent 32/32. The lowest patency rate for the saphenous veins was to the right coronary territory, particularly in off-pump surgery (80.0% vs. 62.5% for the on- respective off-pump groups).CONCLUSIONS: Comparable 5-year patency for the no-touch saphenous veins and the left internal thoracic arteries to the left anterior descending territory in both on- and off-pump coronary artery bypass grafting. Graft patency in off-pump CABG is lower to the right coronary artery.
|
|
| 13. |
|
|
| 14. |
- Björkenheim, Anna, 1980-, et al.
(author)
-
Right ventricular lead perforation with iatrogenic injury to an intercostal artery causing haemothorax after pacemaker implant
- 2024
-
In: BMJ Case Reports. - : BMJ Publishing Group Ltd. - 1757-790X. ; 17:2
-
Journal article (peer-reviewed)abstract
- A woman in her 80s experienced a life-threatening complication of pacemaker implant consisting of subacute right ventricular lead perforation causing iatrogenic injury to an intercostal artery, resulting in a large haemothorax. A CT scan confirmed active bleeding from the fourth intercostal artery. The patient underwent cardiothoracic surgery via a median sternotomy approach, during which the source of the bleeding was sealed, a new epicardial lead was positioned, and the original lead was extracted. This case emphasises the potentially severe consequences of pacemaker lead perforation and secondary injury to adjacent structures. It underscores the importance of early recognition and timely intervention, preferably in a tertiary specialist unit equipped for cardiothoracic surgery and confirms the value of pacemaker interrogation and CT scans for diagnosis.
|
|
| 15. |
- Hellstrandh Jorstig, Stina, 1978-, et al.
(author)
-
Determination of Right Ventricular Volume by Combining Echocardiographic Distance Measurements
- 2016
-
In: Echocardiography. - Hoboken, USA : Wiley-Blackwell Publishing Inc.. - 0742-2822 .- 1540-8175. ; 33:6, s. 844-853
-
Journal article (peer-reviewed)abstract
- Background: The position of the right ventricle (RV), often partly behind the sternum, implies difficulties to image the RV free wall using transthoracic echocardiography (TTE) and consequently limits the possibilities of stroke volume calculations. The aim of this study was to evaluate whether the volume of the right ventricle (RV) can be determined by combining TTE distance measurements that do not need the RV free wall to be fully visualized.Methods: The RV volume was approximated by an ellipsoid composed of three distances. Distance measurements, modeled RV stroke volumes (RVSV), and RV ejection fraction (RVEF) were compared to reference values obtained from cardiac magnetic resonance (CMR) imaging for 12 healthy volunteers.Results: Inter-modality comparisons showed that distance measurements were significantly underestimated in TTE compared to CMR. The modeled RV volumes using TTE distance measurements were underestimated compared to reference CMR volumes. There was, however, for TTE an agreement between modeled RVSV and left ventricular stroke volumes determined by biplane Simpson's rule. Similar agreement was shown between modeled RVSV based on CMR distance measurements and the CMR reference. Regarding RVEF, further studies including patients with a wider range of RVEF are needed to evaluate the method.Conclusion: In conclusion, the ellipsoid model of the RV provides good estimates of RVSVs, but volumes based on distance measurements from different modalities cannot be used interchangeably.
|
|
| 16. |
- Jendeberg, Johan, 1972-, et al.
(author)
-
Differentiation of distal ureteral stones and pelvic phleboliths using a convolutional neural network
- 2021
-
In: Urolithiasis. - : Springer Berlin/Heidelberg. - 2194-7228 .- 2194-7236. ; 49, s. 41-49
-
Journal article (peer-reviewed)abstract
- The objectives were to develop and validate a Convolutional Neural Network (CNN) using local features for differentiating distal ureteral stones from pelvic phleboliths, compare the CNN method with a semi-quantitative method and with radiologists' assessments and to evaluate whether the assessment of a calcification and its local surroundings is sufficient for discriminating ureteral stones from pelvic phleboliths in non-contrast-enhanced CT (NECT). We retrospectively included 341 consecutive patients with acute renal colic and a ureteral stone on NECT showing either a distal ureteral stone, a phlebolith or both. A 2.5-dimensional CNN (2.5D-CNN) model was used, where perpendicular axial, coronal and sagittal images through each calcification were used as input data for the CNN. The CNN was trained on 384 calcifications, and evaluated on an unseen dataset of 50 stones and 50 phleboliths. The CNN was compared to the assessment by seven radiologists who reviewed a local 5 × 5 × 5 cm image stack surrounding each calcification, and to a semi-quantitative method using cut-off values based on the attenuation and volume of the calcifications. The CNN differentiated stones and phleboliths with a sensitivity, specificity and accuracy of 94%, 90% and 92% and an AUC of 0.95. This was similar to a majority vote accuracy of 93% and significantly higher (p = 0.03) than the mean radiologist accuracy of 86%. The semi-quantitative method accuracy was 49%. In conclusion, the CNN differentiated ureteral stones from phleboliths with higher accuracy than the mean of seven radiologists' assessments using local features. However, more than local features are needed to reach optimal discrimination.
|
|
| 17. |
- Jendeberg, Johan, 1972-
(author)
-
Non-enhanced single-energy computed tomography of urinary stones
- 2021
-
Doctoral thesis (other academic/artistic)abstract
- Computed tomography (CT) is the mainstay imaging method for urinary stones.The aim of this thesis was to optimize the information obtained from the initial CT scan to allow a well-founded diagnosis and prognosis, and to guide the clinician as early and as far as possible in the further treatment of urinary stone disease.We examined CT scan parameters with regards to their importance for prediction of spontaneous ureteral stone passage, the impact of interreader variability of stone size estimates on this prediction, and the predictive accuracy of a semi-automated, three-dimensional (3D) segmentation algorithm. We also developed and tested the ability of a machine learning algorithm to classify pelvic calcifications into ureteral stones and phleboliths.Using single-energy CT, three quantitative methods for classification of stone composition into uric acid and non-uric acid stones in vivo were prospectively validated, using dual-energy CT as reference.Our results show that spontaneous ureteral stone passage can be predicted with high accuracy, with knowledge of stone size and position. The interreader variability in the size estimation has a large impact on the predicted outcome, but can be eliminated through a 3D segmentation algorithm. Which size estimate we use is of minor importance, but it is important that we use the chosen estimate consistently. A machine learning algorithm can differentiate distal ureteral stones from phleboliths, but more than local features are needed to reach optimal discrimination.A single-energy CT method can distinguish uric acid from non-uric acid stones in vivo with accuracy comparable to dual-energy CT.In conclusion, single-energy CT not only detects a urinary stone, but can also provide us with a prediction regarding spontaneous stone passage and a classification of stone type into uric acid and non-uric acid.
|
|
| 18. |
- Jendeberg, Johan, 1972-, et al.
(author)
-
Prediction of spontaneous ureteral stone passage : Automated 3D-measurements perform equal to radiologists, and linear measurements equal to volumetric
- 2018
-
In: European Radiology. - : Springer. - 0938-7994 .- 1432-1084. ; 28:6, s. 2474-2483
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: To compare the ability of different size estimates to predict spontaneous passage of ureteral stones using a 3D-segmentation and to investigate the impact of manual measurement variability on the prediction of stone passage.METHODS: We retrospectively included 391 consecutive patients with ureteral stones on non-contrast-enhanced CT (NECT). Three-dimensional segmentation size estimates were compared to the mean of three radiologists' measurements. Receiver-operating characteristic (ROC) analysis was performed for the prediction of spontaneous passage for each estimate. The difference in predicted passage probability between the manual estimates in upper and lower stones was compared.RESULTS: The area under the ROC curve (AUC) for the measurements ranged from 0.88 to 0.90. Between the automated 3D algorithm and the manual measurements the 95% limits of agreement were 0.2 ± 1.4 mm for the width. The manual bone window measurements resulted in a > 20 percentage point (ppt) difference between the readers in the predicted passage probability in 44% of the upper and 6% of the lower ureteral stones.CONCLUSIONS: All automated 3D algorithm size estimates independently predicted the spontaneous stone passage with similar high accuracy as the mean of three readers' manual linear measurements. Manual size estimation of upper stones showed large inter-reader variations for spontaneous passage prediction.KEY POINTS:• An automated 3D technique predicts spontaneous stone passage with high accuracy.• Linear, areal and volumetric measurements performed similarly in predicting stone passage.• Reader variability has a large impact on the predicted prognosis for stone passage.
|
|
| 19. |
|
|
| 20. |
- Jendeberg, Johan, 1972-, et al.
(author)
-
Single-energy CT predicts uric acid stones with accuracy comparable to dual-energy CT-prospective validation of a quantitative method
- 2021
-
In: European Radiology. - : Springer. - 0938-7994 .- 1432-1084. ; 31:8, s. 5980-5989
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: To prospectively validate three quantitative single-energy CT (SE-CT) methods for classifying uric acid (UA) and non-uric acid (non-UA) stones.METHODS: Between September 2018 and September 2019, 116 study participants were prospectively included in the study if they had at least one 3-20-mm urinary stone on an initial urinary tract SE-CT scan. An additional dual-energy CT (DE-CT) scan was performed, limited to the stone of interest. Additionally, to include a sufficient number of UA stones, eight participants with confirmed UA stone on DE-CT were retrospectively included. The SE-CT stone features used in the prediction models were (1) maximum attenuation (maxHU) and (2) the peak point Laplacian (ppLapl) calculated at the position in the stone with maxHU. Two prediction models were previously published methods (ppLapl-maxHU and maxHU) and the third was derived from the previous results based on the k-nearest neighbors (kNN) algorithm (kNN-ppLapl-maxHU). The three methods were evaluated on this new independent stone dataset. The reference standard was the CT vendor's DE-CT application for kidney stones.RESULTS: Altogether 124 participants (59 ± 14 years, 91 men) with 106 non-UA and 37 UA stones were evaluated. For classification of UA and non-UA stones, the sensitivity, specificity, and accuracy were 100% (37/37), 97% (103/106), and 98% (140/143), respectively, for kNN-ppLapl-maxHU; 95% (35/37), 98% (104/106), and 97% (139/143) for ppLapl-maxHU; and 92% (34/37), 94% (100/106), and 94% (134/143) for maxHU.CONCLUSION: A quantitative SE-CT method (kNN-ppLapl-maxHU) can classify UA stones with accuracy comparable to DE-CT.KEY POINTS:• Single-energy CT is the first-line diagnostic tool for suspected renal colic.• A single-energy CT method based on the internal urinary stone attenuation distribution can classify urinary stones into uric acid and non-uric acid stones with high accuracy.• This immensely increases the availability of in vivo stone analysis.
|
|
| 21. |
|
|
| 22. |
- Jendeberg, Johan, 1972-, et al.
(author)
-
Size matters : The width and location of a ureteral stone accurately predict the chance of spontaneous passage
- 2017
-
In: European Radiology. - : Springer. - 0938-7994 .- 1432-1084. ; 27:11, s. 4775-4785
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: To determine how to most accurately predict the chance of spontaneous passage of a ureteral stone using information in the diagnostic non-enhanced computed tomography (NECT) and to create predictive models with smaller stone size intervals than previously possible.METHODS: Retrospectively 392 consecutive patients with ureteric stone on NECT were included. Three radiologists independently measured the stone size. Stone location, side, hydronephrosis, CRP, medical expulsion therapy (MET) and all follow-up radiology until stone expulsion or 26 weeks were recorded. Logistic regressions were performed with spontaneous stone passage in 4 weeks and 20 weeks as the dependent variable.RESULTS: The spontaneous passage rate in 20 weeks was 312 out of 392 stones, 98% in 0-2 mm, 98% in 3 mm, 81% in 4 mm, 65% in 5 mm, 33% in 6 mm and 9% in ≥6.5 mm wide stones. The stone size and location predicted spontaneous ureteric stone passage. The side and the grade of hydronephrosis only predicted stone passage in specific subgroups.CONCLUSION: Spontaneous passage of a ureteral stone can be predicted with high accuracy with the information available in the NECT. We present a prediction method based on stone size and location.KEY POINTS: • Non-enhanced computed tomography can predict the outcome of ureteral stones. • Stone size and location are the most important predictors of spontaneous passage. • Prediction models based on stone width or length and stone location are introduced. • The observed passage rates for stone size in mm-intervals are reported. • Clinicians can make better decisions about treatment.
|
|
| 23. |
- Jorstig, Stina, 1978-, et al.
(author)
-
Distance and area measurement of the right atrium and ventricle by echocardiography and cardiac magnetic resonance imaging : do we measure the same thing?
- 2016
-
Conference paper (other academic/artistic)abstract
- Purpose: It has previously been shown that stroke volumes measured by transthoracic echocardiography (TTE) are underestimated, compared to cardiac magnetic resonance (CMR) imaging. The purpose of this study was to evaluate differences in distance and area measurements of the right atrium (RA) and the right ventricle (RV) by TTE and CMR.Methods: TTE examinations and CMR examinations were subsequently performed in 12 healthy volunteers. Three distances (RAL - right atrial length, RVIT3 - right ventricular inflow tract, RVLAX - right ventricular long axis) and one area (RVA - right ventricular area) were measured in TTE and CMR. Stroke volumes were also calculated using conventional methods available on each modality. Both intramodality and intermodality comparisons were performed based on measurements from three observers. One of the observers performed measurements in both TTE and CMR.Results: Intermodality comparisons showed that all distance and area measurements were significantly smaller using TTE (Table 1). Two of the measurements, RVIT3 and RVA, differed at about 50%. Calculated stroke volumes showed, consistent with previous results, that the TTE stroke volumes are substantially underestimated compared to CMR volumes. Intramodality variations of distance and area measurements were considerably smaller (Table 1).Conclusions: Our results show that RV distances and areas measured by TTE are smaller compared to CMR, probably due to differences in defining the endocardial borders. These differences subsequently result in smaller stroke volumes when using TTE. Caution should be taken when comparing distances, areas and volumes measured by TTE and CMR.
|
|
| 24. |
- Jorstig, Stina Hellstrand, 1978-, et al.
(author)
-
A study to determine the contribution to right ventricle stroke volume from pulmonary and tricuspid valve displacement volumes
- 2015
-
In: Clinical Physiology and Functional Imaging. - : Wiley-Blackwell. - 1475-0961 .- 1475-097X. ; 35:4, s. 283-290
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Describing the systolic function of the right ventricle (RV) is a difficult task due to the complex shape and orientation of the RV. The purpose of this study was to investigate the extent to which the volumes encompassed by the pulmonary and tricuspid valve displacements contribute to the total right ventricle stroke volume (RVSV).METHODS: Twelve healthy volunteers were examined using cardiac magnetic resonance (CMR). Two series of time-resolved axially rotated MR images were acquired that encompassed the tricuspid valve and the pulmonary valve, respectively. The volume related to each valve movement, the tricuspid plane displacement (TPD) and the pulmonary plane displacement (PPD), was determined by delineation in diastole and systole. These volumes, RVSVTPD and RVSVPPD , were compared to the stroke volume to determine the contributions to the total stroke volume from the TPD and the PPD. The remaining volume of the total RVSV was referred to as RVSVOther . An initial in vitro study was carried out to validate the accuracy of volume measurements using axially rotated images.RESULTS: In vitro measurements indicated that the method for volumetric measurements using axially rotated images was a very accurate one, with a mean difference of 0·04 ± 0·10 ml. The in vivo measurements of RVSVTPD , RVSVPPD and RVSVOther were 45 ± 10%, 13 ± 2% and 42 ± 11%, respectively.CONCLUSIONS: Right ventricle stroke volume is determined by different individual volume changes as follows: RVSVTPD together with RVSVOther contributes to almost the entire RVSV in nearly equal proportions, while RVSVPPD contributes only a small amount and is approximately 30% of either RVSVTPD or RVSVOther.
|
|
| 25. |
- Jorstig, Stina, 1978-, et al.
(author)
-
Right ventricular ejection fraction measurements using two-dimensional transthoracic echocardiography by applying an ellipsoid model
- 2017
-
In: Cardiovascular Ultrasound. - : BioMed Central. - 1476-7120. ; 15
-
Journal article (peer-reviewed)abstract
- Background: There is today no established approach to estimate right ventricular ejection fraction (RVEF) using 2D transthoracic echocardiography (TTE). The aim of this study was to evaluate a new method for RVEF calculations using 2D TTE and compare the results with cardiac magnetic resonance (CMR) imaging and tricuspid annular plane systolic excursion (TAPSE).Methods: A total of 37 subjects, 25 retrospectively included patients and twelve healthy volunteers, were included to give a wide range of RVEF. The right ventricle (RV) was modeled as a part of an ellipsoid enabling calculation of the RV volume by combining three distance measurements. RVEF calculated according to the model, RVEFTTE, were compared with reference CMR-derived RVEF, RVEFCMR. Further, TAPSE was measured in the TTE images and the correlations were calculated between RVEFTTE, TAPSE and RVEFCMR.Results: The mean values were RVEFCMR = 43 +/- 12% (range 20-66%) and RVEFTTE = 50 +/- 9% (range 34-65%). There was a high correlation (r = 0.80, p < 0.001) between RVEFTTE and RVEFCMR. Bland-Altman analysis showed a mean difference between RVEFCMR and RVEFTTE of 6 percentage points (ppt) with limits of agreement from -11 to 23 ppt. The mean value for TAPSE was 19 +/- 5 mm and the correlation between TAPSE and RVEFCMR was moderate (r = 0.54, p < 0.001). The correlation between RVEFTTE and RVEFCMR was significantly higher (p < 0.05) than the correlation between TAPSE and RVEFCMR.Conclusions: The ellipsoid model shows promise for RVEF calculations using 2D TTE for a wide range of RVEF, providing RVEF estimates that were significantly better correlated to RVEF obtained from CMR compared to TAPSE.
|
|
| 26. |
|
|
| 27. |
- Krauss, Wolfgang, 1973-, et al.
(author)
-
Radiomics from multisite MRI and clinical data to predict clinically significant prostate cancer
- 2024
-
In: Acta Radiologica. - : Sage Publications. - 0284-1851 .- 1600-0455. ; 23:1
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Magnetic resonance imaging (MRI) is useful in the diagnosis of clinically significant prostate cancer (csPCa). MRI-derived radiomics may support the diagnosis of csPCa. PURPOSE: To investigate whether adding radiomics from biparametric MRI to predictive models based on clinical and MRI parameters improves the prediction of csPCa in a multisite-multivendor setting.MATERIAL AND METHODS: Clinical information (PSA, PSA density, prostate volume, and age), MRI reviews (PI-RADS 2.1), and radiomics (histogram and texture features) were retrieved from prospectively included patients examined at different radiology departments and with different MRI systems, followed by MRI-ultrasound fusion guided biopsies of lesions PI-RADS 3-5. Predictive logistic regression models of csPCa (Gleason score ≥7) for the peripheral (PZ) and transition zone (TZ), including clinical data and PI-RADS only, and combined with radiomics, were built and compared using receiver operating characteristic (ROC) curves.RESULTS: In total, 456 lesions in 350 patients were analyzed. In PZ and TZ, PI-RADS 4-5 and PSA density, and age in PZ, were independent predictors of csPCa in models without radiomics. In models including radiomics, PI-RADS 4-5, PSA density, age, and ADC energy were independent predictors in PZ, and PI-RADS 5, PSA density and ADC mean in TZ. Comparison of areas under the ROC curve (AUC) for the models without radiomics (PZ: AUC = 0.82, TZ: AUC = 0.80) versus with radiomics (PZ: AUC = 0.82, TZ: AUC = 0.82) showed no significant differences (PZ: P = 0.366; TZ: P = 0.171).CONCLUSION: PSA density and PI-RADS are potent predictors of csPCa. Radiomics do not add significant information to our multisite-multivendor dataset.
|
|
| 28. |
- Lidén, Mats, 1976-
(author)
-
A new method for predicting uric acid composition in urinary stones using routine single-energy CT
- 2018
-
In: Urolithiasis. - : Springer. - 2194-7228 .- 2194-7236. ; 46:4, s. 325-332
-
Journal article (peer-reviewed)abstract
- Urinary stones composed of uric acid can be treated medically. Prediction of uric acid stone type is, therefore, desirable when a urinary stone is diagnosed with unenhanced CT. The purpose of the present study was to describe single-energy thin slice quantitative CT parameters of urinary stones correlated to chemical stone type and to develop a method to distinguish pure uric acid stones (UA) from other stones (non-UA/Mix). Unenhanced thin slice single-energy CT images of 126 urinary stones (117 patients) with known chemical stone type were retrospectively included in the study. Among the included stones, 22 were UA and 104 were non-UA/Mix. The included CT images and Laplacian filtered images of the stones were quantitatively analyzed using operator-independent methods. A post hoc classification method for pure UA stones was created using a combination of cutoff values for the peak attenuation and peak point Laplacian. The stone types differed in most quantitative image characteristics including mean attenuation (p < 0.001), peak attenuation (p < 0.001), and peak point Laplacian (p < 0.001). The sensitivity for the post hoc-developed peak attenuation-peak point Laplacian method for classifying pure UA stones was 95% [21/22, 95% CI (77-100%)] and the specificity was 99% [103/104, 95% CI (95-100%)]. In conclusion, quantitative image analysis of thin slice routine single-energy CT images is promising for predicting pure UA content in urinary stones, with results comparable to double energy methods.
|
|
| 29. |
- Lidén, Mats, 1976-, et al.
(author)
-
Discrimination between distal ureteral stones and pelvic phleboliths in CT using a deep neural network : more than local features needed
- 2018
-
Conference paper (peer-reviewed)abstract
- Purpose: To develop a deep learning method for assisting radiologists in the discrimination between distal ureteral stones and pelvic phleboliths in thin slice CT images, and to evaluate whether this differentiation is possible using only local features.Methods and materials: A limited field-of-view image data bank was retrospectively created, consisting of 5x5x5 cm selections from 1 mm thick unenhanced CT images centered around 218 pelvis phleboliths and 267 distal ureteral stones in 336 patients. 50 stones and 50 phleboliths formed a validation cohort and the remainder a training cohort. Ground truth was established by a radiologist using the complete CT examination during inclusion.The limited field-of-view CT stacks were independently reviewed and classified as containing a distal ureteral stone or a phlebolith by seven radiologists. Each cropped stack consisted of 50 slices (5x5 cm field-of-view) and was displayed in a standard PACS reading environment. A convolutional neural network using three perpendicular images (2.5D-CNN) from the limited field-of-view CT stacks was trained for classification.Results: The 2.5D-CNN obtained 89% accuracy (95% confidence interval 81%-94%) for the classification in the unseen validation cohort while the accuracy of radiologists reviewing the same cohort was 86% (range 76%-91%). There was no statistically significant difference between 2.5D-CNN and radiologists.Conclusion: The 2.5D-CNN achieved radiologist level classification accuracy between distal ureteral stones and pelvic phleboliths when only using the local features. The mean accuracy of 86% for radiologists using limited field-of-view indicates that distant anatomical information that helps identifying the ureter’s course is needed.
|
|
| 30. |
- Lidén, Mats, 1976-, et al.
(author)
-
Impact of Heart Rate on Flow Measurements in Aortic Regurgitation
- 2017
-
In: Journal of Heart Valve Disease. - : I C R Publishers Ltd.. - 0966-8519 .- 2053-2644. ; 26:5, s. 502-508
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Flow measurements using cardiac magnetic resonance imaging (CMRI) enable quantification of the stroke volume, regurgitant volume (RV) and regurgitant fraction (RF) in patients with aortic regurgitation (AR). These variables are used to assess the severity of the valve disease and for the timing of surgery. The aim of the study was to investigate the impact of an increased heart rate on measurement of the RV and RF in patients with AR.METHODS: Among 13 patients with known moderate or severe AR, regurgitant flow measurements, using phase-contrast cine magnetic resonance imaging, were obtained in the ascending aorta. Flow measurements were obtained at rest and at increased heart rates after intravenous administration of atropine.RESULTS: The mean heart rate was 61 beats per min at rest and 91 beats per min after atropine administration. The RV and RF were 52 ml and 35% at rest, respectively, and 34 ml (p <0.001) and 30% (p = 0.065) at increased heart rate, respectively.CONCLUSIONS: An increased heart rate leads to a decreased RV. The RF is more stable and may therefore be preferable for severity grading in AR.
|
|
| 31. |
- Lidén, Mats, 1976-, et al.
(author)
-
Machine learning slice-wise whole-lung CT emphysema score correlates with airway obstruction
- 2024
-
In: European Radiology. - : Springer. - 0938-7994 .- 1432-1084. ; 34:1, s. 39-49
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: Quantitative CT imaging is an important emphysema biomarker, especially in smoking cohorts, but does not always correlate to radiologists' visual CT assessments. The objectives were to develop and validate a neural network-based slice-wise whole-lung emphysema score (SWES) for chest CT, to validate SWES on unseen CT data, and to compare SWES with a conventional quantitative CT method.MATERIALS AND METHODS: Separate cohorts were used for algorithm development and validation. For validation, thin-slice CT stacks from 474 participants in the prospective cross-sectional Swedish CArdioPulmonary bioImage Study (SCAPIS) were included, 395 randomly selected and 79 from an emphysema cohort. Spirometry (FEV1/FVC) and radiologists' visual emphysema scores (sum-visual) obtained at inclusion in SCAPIS were used as reference tests. SWES was compared with a commercially available quantitative emphysema scoring method (LAV950) using Pearson's correlation coefficients and receiver operating characteristics (ROC) analysis.RESULTS: SWES correlated more strongly with the visual scores than LAV950 (r = 0.78 vs. r = 0.41, p < 0.001). The area under the ROC curve for the prediction of airway obstruction was larger for SWES than for LAV950 (0.76 vs. 0.61, p = 0.007). SWES correlated more strongly with FEV1/FVC than either LAV950 or sum-visual in the full cohort (r = - 0.69 vs. r = - 0.49/r = - 0.64, p < 0.001/p = 0.007), in the emphysema cohort (r = - 0.77 vs. r = - 0.69/r = - 0.65, p = 0.03/p = 0.002), and in the random sample (r = - 0.39 vs. r = - 0.26/r = - 0.25, p = 0.001/p = 0.007).CONCLUSION: The slice-wise whole-lung emphysema score (SWES) correlates better than LAV950 with radiologists' visual emphysema scores and correlates better with airway obstruction than do LAV950 and radiologists' visual scores.CLINICAL RELEVANCE STATEMENT: The slice-wise whole-lung emphysema score provides quantitative emphysema information for CT imaging that avoids the disadvantages of threshold-based scores and is correlated more strongly with reference tests than LAV950 and reader visual scores.KEY POINTS: • A slice-wise whole-lung emphysema score (SWES) was developed to quantify emphysema in chest CT images. • SWES identified visual emphysema and spirometric airflow limitation significantly better than threshold-based score (LAV950). • SWES improved emphysema quantification in CT images, which is especially useful in large-scale research.
|
|
| 32. |
- Lidén, Mats, 1976-, et al.
(author)
-
Multi-Reader-Multi-Split Annotation of Emphysema in Computed Tomography
- 2020
-
In: Journal of digital imaging. - : Springer. - 0897-1889 .- 1618-727X. ; 33:5, s. 1185-1193
-
Journal article (peer-reviewed)abstract
- Emphysema is visible on computed tomography (CT) as low-density lesions representing the destruction of the pulmonary alveoli. To train a machine learning model on the emphysema extent in CT images, labeled image data is needed. The provision of these labels requires trained readers, who are a limited resource. The purpose of the study was to test the reading time, inter-observer reliability and validity of the multi-reader-multi-split method for acquiring CT image labels from radiologists. The approximately 500 slices of each stack of lung CT images were split into 1-cm chunks, with 17 thin axial slices per chunk. The chunks were randomly distributed to 26 readers, radiologists and radiology residents. Each chunk was given a quick score concerning emphysema type and severity in the left and right lung separately. A cohort of 102 subjects, with varying degrees of visible emphysema in the lung CT images, was selected from the SCAPIS pilot, performed in 2012 in Gothenburg, Sweden. In total, the readers created 9050 labels for 2881 chunks. Image labels were compared with regional annotations already provided at the SCAPIS pilot inclusion. The median reading time per chunk was 15 s. The inter-observer Krippendorff's alpha was 0.40 and 0.53 for emphysema type and score, respectively, and higher in the apical part than in the basal part of the lungs. The multi-split emphysema scores were generally consistent with regional annotations. In conclusion, the multi-reader-multi-split method provided reasonably valid image labels, with an estimation of the inter-observer reliability.
|
|
| 33. |
- Lidén, Mats, 1976-, et al.
(author)
-
Quantitative T2* imaging of iron overload in a non-dedicated center - Normal variation, repeatability and reader variation
- 2021
-
In: European journal of radiology open. - : Elsevier. - 2352-0477. ; 8
-
Journal article (peer-reviewed)abstract
- Background: Patients with transfusion dependent anemia are at risk of complications from iron overload. Quantitative T2* magnetic resonance imaging (MRI) is the best non-invasive method to assess iron deposition in the liver and heart and to guide chelation therapy.Purpose: To investigate the image quality and inter-observer variations in T2* measurements of the myocardium and the liver, and to obtain the lower limit of cardiac and hepatic quantitative T2* values in patients without suspicion of iron overload.Material and methods: Thirty-eight patients referred for cardiac MRI were prospectively included in the study. Three patients were referred with, and 35 without suspicion of iron overload. Quantitative T2* parametric maps were obtained on a 1.5 T MRI system in the cardiac short axis and liver axial view. Two readers independently assessed the image quality and the representative and the lowest T2* value in the myocardium and the liver.Results: The normal range of representative T2* values in the myocardium and liver was 24-45 ms and 14-37 ms, respectively. None of the 35 participants (0 %, 95 % confidence interval 0-11 %) in the normal reference group demonstrated representative T2* values below previously reported lower limits in the myocardium (20 ms) or the liver (8 ms). Focal myocardial areas with T2* values near the lower normal range, 19-20 ms, were seen in two patients. The readers generally reported good image quality.Conclusion: T2* imaging for assessing iron overload can be performed in a non-dedicated center with sufficient image quality.
|
|
| 34. |
- Lidén, Mats, 1976-, et al.
(author)
-
Two- and three-dimensional CT measurements of urinary calculi length and width : a comparative study
-
Other publication (other academic/artistic)abstract
- The standard imaging procedure for a patient presenting with renal colic is unenhanced CT. The CT measured size has a close correlation to the estimated prognosis for spontaneous passage of a ureteral calculus. Size estimations of urinary calculi in CT images are still based on 2d-reformats. In the present study we developed and validated a calculus oriented 3dmethod for measurements of length and width of urinary calculi and compared those with corresponding 2d measurements in axial and coronal reformats.Methods: Fifty unenhanced CT examinations demonstrating urinary calculi were included. A 3d-symmetric segmentation algorithm was validated against reader size estimations. The calculus-oriented size from the segmentation was then compared to the size in axial and coronal reformats.Results: The validation showed 0.1±0.7 mm agreement against reference measure. There was a 0.4 mm median bias for 3d-estimated calculus length compared to 2d (p<0.001), but no significant bias for 3d-width compared to 2d.Conclusion: The size of the urinary calculus becomes underestimated if its orientation is not aligned to the axial or coronal image plane. Future studies aiming to correlate calculus size with patient outcome should use a calculus oriented size estimation.
|
|
| 35. |
- Lidén, Mats, 1976-, et al.
(author)
-
Urinary stone size estimation : a new segmentation algorithm-based CT method
- 2012
-
In: European Radiology. - New York, USA : Springer. - 0938-7994 .- 1432-1084. ; 22:4, s. 731-737
-
Journal article (peer-reviewed)abstract
- The size estimation in CT images of an obstructing ureteral calculus is important for the clinical management of a patient presenting with renal colic. The objective of the present study was to develop a reader independent urinary calculus segmentation algorithm using well-known digital image processing steps and to validate the method against size estimations by several readers. Fifty clinical CT examinations demonstrating urinary calculi were included. Each calculus was measured independently by 11 readers. The mean value of their size estimations was used as validation data for each calculus. The segmentation algorithm consisted of interpolated zoom, binary thresholding and morphological operations. Ten examinations were used for algorithm optimisation and 40 for validation. Based on the optimisation results three segmentation method candidates were identified. Between the primary segmentation algorithm using cubic spline interpolation and the mean estimation by 11 readers, the bias was 0.0 mm, the standard deviation of the difference 0.26 mm and the Bland-Altman limits of agreement 0.0 +/- 0.5 mm. The validation showed good agreement between the suggested algorithm and the mean estimation by a large number of readers. The limit of agreement was narrower than the inter-reader limit of agreement previously reported for the same data. The size of kidney stones is usually estimated manually by the radiologist. An algorithm for computer-aided size estimation is introduced. The variability between readers can be reduced. A reduced variability can give better information for treatment decisions.
|
|
| 36. |
|
|
| 37. |
- Lundin, Margareta, et al.
(author)
-
Virtual non-contrast dual-energy CT compared to single-energy CT of the urinary tract : a prospective study
- 2012
-
In: Acta Radiologica. - : Informa Healthcare. - 0284-1851 .- 1600-0455. ; 53:6, s. 689-694
-
Journal article (peer-reviewed)abstract
- Background: Dual-energy computed tomography (DECT) has been shown to be useful for subtracting bone or calcium in CT angiography and gives an opportunity to produce a virtual non-contrast-enhanced (VNC) image from a series where contrast agents have been given intravenously. High noise levels and low resolution have previously limited the diagnostic value of the VNC images created with the first generation of DECT. With the recent introduction of a second generation of DECT, there is a possibility of obtaining VNC images with better image quality at hopefully lower radiation dose compared to the previous generation.Purpose: The aim of this study is to compare the image quality of the single-energy series to a VNC series obtained with a two generations of DECT scanners. CT of the urinary tract was used as a model.Material and Methods: Thirty patients referred for evaluation of haematuria were examined with an older system (Somatom Definition) and another 30 patients with a new generation (Somatom Definition Flash). One single-energy series was obtained before and one dual-energy series after administration of intravenous contrast media. We created a VNC series from the contrast-enhanced images. Images were assessed concerning image quality with a visual grading scale evaluation of the VNC series with the single-energy series as gold standard.Results: The image quality of the VNC images was rated inferior to the single-energy variant for both scanners, OR range 11.5-67.3 for the Definition and OR 2.1-2.8 for the Definition Flash. Visual noise and overall quality were regarded as better with Flash than Definition.Conclusions: Image quality of VNC images obtained with the new generation of DECT is still slightly inferior compared to native images. However the difference is smaller with the new compared to the older system.
|
|
| 38. |
- Längkvist, Martin, 1983-, et al.
(author)
-
Computer aided detection of ureteral stones in thin slice computed tomography volumes using Convolutional Neural Networks
- 2018
-
In: Computers in Biology and Medicine. - : Elsevier. - 0010-4825 .- 1879-0534. ; 97, s. 153-160
-
Journal article (peer-reviewed)abstract
- Computed tomography (CT) is the method of choice for diagnosing ureteral stones - kidney stones that obstruct the ureter. The purpose of this study is to develop a computer aided detection (CAD) algorithm for identifying a ureteral stone in thin slice CT volumes. The challenge in CAD for urinary stones lies in the similarity in shape and intensity of stones with non-stone structures and how to efficiently deal with large high-resolution CT volumes. We address these challenges by using a Convolutional Neural Network (CNN) that works directly on the high resolution CT volumes. The method is evaluated on a large data base of 465 clinically acquired high-resolution CT volumes of the urinary tract with labeling of ureteral stones performed by a radiologist. The best model using 2.5D input data and anatomical information achieved a sensitivity of 100% and an average of 2.68 false-positives per patient on a test set of 88 scans.
|
|
| 39. |
- Månsson, Jonas, et al.
(author)
-
COVID-19 Across Professions - Infection, Hospitalisation, and ICU Patterns in a Swedish County
- 2024
-
In: Journal of Occupational and Environmental Medicine. - : Lippincott Williams & Wilkins. - 1076-2752 .- 1536-5948.
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: To study infection, hospitalisation, and admission to ICU for COVID-19 in different occupations and pandemic waves in a Swedish county.METHODS: Individual registry data of infection and hospitalisation were merged with occupational data in, this cross-sectional study. Infected, hospital- and ICU-admission were analysed by occupational groups.RESULTS: 22,095 cases of COVID-19 from 21 February 2021 to 31 August 2022 were identified. Healthcare workers and others working in close physical proximity showed a higher rate of confirmed COVID-19 infections in all waves and higher risk for hospital admission early in the pandemic. Exposure to diseases and physical proximity played a decisive role.CONCLUSION: Workers in close-contact occupations experienced a higher rate of confirmed infections throughout the pandemic and higher hospitalisation rates in the first pandemic wave, suggesting a need for more effective initial safety measures in a future pandemic.
|
|
| 40. |
- Nyman, Ulf, et al.
(author)
-
Revised Swedish guidelines on intravenous iodine contrast medium-induced acute kidney injury 2022: A summary
- 2023
-
In: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 64:5
-
Research review (peer-reviewed)abstract
- The Swedish Society of Uroradiology has revised their computed tomography (CT) guidelines regarding iodine contrast media-induced acute kidney injury (CI-AKI). They are more cautious compared to the European Society of Urogenital Radiology and the American College of Radiology since the actual risk of CI-AKI remains uncertain in patients with moderate to severe kidney damage due to a lack of prospective controlled studies and mainly based on retrospective propensity score-matched studies with low-grade evidence. Another source of uncertainty is the imprecision of glomerular filtration rate (GFR) estimating equations. However, randomized hydration studies indictae an upper limit risk of CI-AKI of about 5% for outpatients with a GFR in the range of 30-44 or 45-59 mL/min/1.73m(2) combined with multiple risk factors. Apart from GFR limits, the guideline also includes limits for systemic contrast medium exposure expressed in gram-iodine/GFR ratio.
|
|
| 41. |
- Papmehl-Dufay, Ludvig, 1976-
(author)
-
Shaping an identity : Pitted Ware pottery and potters in southeast Sweden
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- The thesis is concerned with pottery and culture during the Middle Neolithic (c. 3300 – 2300 cal BC) in southeast Sweden. Its purpose is to investigate and discuss the significance of pottery in the Pitted Ware culture, particularly on the island of Öland in the Baltic Sea. The history of research concerning this subject area is recounted and the known Neolithic remains from the island of Öland are reviewed. The two Pitted Ware sites so far excavated on the island, Köpingsvik and Ottenby Royal Manor, are presented in detail, and ceramics from these two sites are used in the pottery analysis that makes up the empirical core of the work. The assemblages are approached by similar methods and by posing similar questions, and the analytical methods used include recording of the large ceramic assemblages (aspects of design), microscopic analysis of ceramic thin sections and raw clay samples (aspects of raw material use and pottery technology) and lipid residue analysis performed on extracts from pulverised ceramic ware (aspects of pottery use). The results clearly point to a rather elaborate and socially embedded ceramic craft tradition, with a strong preference for decorated vessels and clearly defined ideas on how the pots should be produced and what they should look like. The technological analysis revealed a rather complicated and restrictive raw material situation, with which the potters coped partly by developing local tempering traditions. The functional analysis revealed a striking variability in pottery use between the two sites. The various differences in pottery observed between the two sites are discussed in terms of local sub-traditions within the overall Pitted Ware ceramic tradition, that may have developed through the work of individual potters and contacts with different areas and groups of people. In this way an attempt is made to view pottery and the ceramic craft in the Pitted Ware culture from a more dynamic perspective.
|
|
| 42. |
|
|
| 43. |
- Popiolek, Marcin, 1981-, et al.
(author)
-
Finding the optimal candidate for shock wave lithotripsy : external validation and comparison of five prediction models
- 2023
-
In: Urolithiasis. - : Springer. - 2194-7228 .- 2194-7236. ; 51:1
-
Journal article (peer-reviewed)abstract
- We aimed to externally validate five previously published predictive models (Ng score, Triple D score, S3HoCKwave score, Kim nomogram, Niwa nomogram) for shock wave lithotripsy (SWL) single-session outcomes in patients with a solitary stone in the upper ureter. The validation cohort included patients treated with SWL from September 2011 to December 2019 at our institution. Patient-related variables were retrospectively collected from the hospital records. Stone-related data including all measurements were retrieved from computed tomography prior to SWL. We estimated discrimination using area under the curve (AUC), calibration, and clinical net benefit based on decision curve analysis (DCA). A total of 384 patients with proximal ureter stones treated with SWL were included in the analysis. Median age was 55.5 years, and 282 (73%) of the sample were men. Median stone length was 8.0 mm. All models significantly predicted the SWL outcomes after one session. S3HoCKwave score, Niwa, and Kim nomograms had the highest accuracy in predicting outcomes, with AUC 0.716, 0.714 and 0.701, respectively. These three models outperformed both the Ng (AUC: 0.670) and Triple D (AUC: 0.667) scoring systems, approaching statistical significance (P = 0.05). Of all the models, the Niwa nomogram showed the strongest calibration and highest net benefit in DCA. To conclude, the models showed small differences in predictive power. The Niwa nomogram, however, demonstrated acceptable discrimination, the most accurate calibration, and the highest net benefit whilst having relatively simple design. Therefore, it could be useful for counselling patients with a solitary stone in the upper ureter.
|
|
| 44. |
- Samano, Ninos, 1972-, et al.
(author)
-
The no-touch saphenous vein for coronary artery bypass grafting maintains a patency, after 16 years, comparable to the left internal thoracic artery : a randomized trial
- 2015
-
In: Journal of Thoracic and Cardiovascular Surgery. - : Mosby-Elsevier. - 0022-5223 .- 1097-685X. ; 150:4, s. 880-888
-
Journal article (peer-reviewed)abstract
- Objectives: This study investigates whether the no-touch (NT) vein graft, at a mean time of 16 years, maintains a significantly higher patency rate than conventional (C) vein grafts and still has patency comparable to that of the left internal thoracic artery (LITA).Methods: A total of 156 patients accepted for coronary artery bypass grafting were randomly allocated to 1 of 3 groups. In the C group, the saphenous vein (SV) was stripped and distended. In the intermediate group, the SV was stripped but not distended. In the NT group, the SV was neither stripped nor distended, but rather harvested with a fat pedicle. This study is an angiographic follow-up of the C and NT groups, at a mean time of 16 years postoperatively.Results: Fifty-four patients were included (C group = 27; NT group = 27). In all, 72 and 75 vein grafts were completed in groups C and NT, respectively. Crude SV graft patency was 64% in the C group versus 83% in the NT group (P = .03), which was similar to the patency of the LITA (88%). The harvesting technique had a major impact on the patency with a hazard ratio for occlusion of 1.83 for the C group (P = .04).Conclusions: Harvesting the SV with the NT technique conferred, at a mean time of 16 years, a significantly higher patency than the conventional technique that was still comparable to that of the LITA.
|
|
| 45. |
- Schagatay, Felix, et al.
(author)
-
Serum concentration of extracellular cold-inducible RNA-binding protein is associated with respiratory failure in COVID-19
- 2022
-
In: Frontiers in Immunology. - : Frontiers Media S.A.. - 1664-3224. ; 13
-
Journal article (peer-reviewed)abstract
- Uncontrolled release of damage-associated molecular patterns (DAMPs) is suggested to be a major trigger for the dysregulated host immune response that leads to severe COVID-19. Cold-inducible RNA-binding protein (CIRP), is a newly identified DAMP that aggravates inflammation and tissue injury, and induces respiratory failure in sepsis. Whether CIRP contributes to the pathogenesis of respiratory failure in COVID-19 has not yet been explored.Aim: To investigate if the concentration of extracellular CIRP (eCIRP) in serum associates with respiratory failure and lung involvement by chest computed tomography (CT) in COVID-19.Methods: Herein we report a prospective observational study of patients with COVID-19 included at two University Hospitals in Sweden between April 2020 and May 2021. Serum from hospitalized patients in Örebro (N=97) were used to assess the association between eCIRP and the level of respiratory support and its correlation with pulmonary involvement on chest CT and inflammatory biomarkers. A cohort of hospitalized and non-hospitalized patients from Umeå (N=78) was used as an external validation cohort. The severity of disease was defined according to the highest degree of respiratory support; mild disease (no oxygen), non-severe hypoxemia (conventional oxygen or high-flow nasal oxygen, HFNO <50% FiO2), and severe hypoxemia (HFNO ≥50% FiO2, mechanical ventilation). Unadjusted and adjusted linear regression was used to evaluate peak eCIRP day 0-4 in respect to severity, age, sex, Charlson comorbidity score, symptom duration, and BMI.Results: Peak eCIRP concentrations were higher in patients with severe hypoxemia and were independently associated with the degree of respiratory support in both cohorts (Örebro; p=0.01, Umeå; p<0.01). The degree of pulmonary involvement measured by CT correlated with eCIRP, rs=0.30, p<0.01 (n=97).Conclusion: High serum levels of eCIRP are associated with acute respiratory failure in COVID-19. Experimental studies are needed to determine if treatments targeting eCIRP reduces the risk of acute respiratory failure in COVID-19.
|
|
| 46. |
- Waldenborg, Micael, 1981-, et al.
(author)
-
Effect on left ventricular mass and geometry in patients with takotsubo cardiomyopathy
- 2015
-
In: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1401-7431 .- 1651-2006. ; 49:1, s. 27-38
-
Journal article (peer-reviewed)abstract
- Objectives: Takotsubo cardiomyopathy (TTC) is a condition of transient left ventricular (LV) dysfunction. The effects on LV mass (LVM) and geometry have not been studied enough in TTC. Retrospectively, we analyzed our TTC cohort both by transthoracic echocardiography (TTE) and magnetic resonance imaging (MRI), for comparative purposes.Design: Thirteen women undergoing TTE and MRI, at onset and three months later, were included. LVM was estimated by MRI, and two TTE-methods. Segmental wall thickness (SWT) was measured, whilst radial strain was assessed by TTE. Data analysis included Wilcoxon's test (between phases), Mann Whitney U- and McNemar's tests (between and within groups). Bland-Altman analyzes were used for intertechnique coherence, whilst interactions regarding TTE were tested using Spearman's coefficient.Results: LVM decreased during recovery (p<0.05), by MRI and one of the TTE-methods; truncated ellipsoid formula (TEF), which also showed relatively better coherence compared to MRI. SWT decreased in two of three sites, by both modalities, but with ambiguous coherence therebetween. The TEF-data interacted partially with a demonstrated increase in radial strain.Conclusions: TTC associates with acute increase in LVM, which appears to be an apical effect, tending to follow the changes in concentric wall motion. MRI and TTE show adequate coherence; primarily for the TEF-method regarding LVM.
|
|
| 47. |
- Waldenborg, Micael, 1981-, et al.
(author)
-
Effect on left ventricular mass and geometry in patients with takotsubo cardiomyopathy
-
Other publication (other academic/artistic)abstract
- Aims: Takotsubo cardiomyopathy (TTC) is a condition of reversible left ventricular (LV) dysfunction. The effects, from acute to recovery phase, on LV mass (LVM) and the LV geometry are not thoroughly enough studied at TTC, which were the main aims of the present study. Retrospectively, we analyzed our cohort of TTC-patients, both with transthoracic echocardiography (TTE) and magnetic resonance imaging (MRI), to further investigate these changes, including intertechnique comparison.Methods: We studied 13 female TTC-patients, undergoing TTE and MRI acutely, and three months later at follow-up. LVM was measured with MRI- and five different TTE-methods. Segmental wall thickness (SWT) was assessed, and used for LV hypertrophy (LVH) geometry categorization. Radial strain was measured at TTE. Data analysis included Wilcoxon signed-test (between phases), Mann Whitney U- and McNemar’s tests (between and within groups). Spearman’s coefficient was used for intertechnique coherence (with BlandAltman plots) and for correlations of simultaneous TTE changes.Results: LVM decreased significantly between phases (p<0.05), by MRI and with two TTE-methods. Two of three SWT-sites became significantly thinner, with adequate correlation (rs≥0.69) between techniques, while LVH categories remained unchanged. Relatively better consistency, compared with MRI, was shown for one of the TTE-methods used to estimate LVM (truncated ellipsoid (TE)). Radial strain improved significantly, with partial correlation towards the TE-method.Conclusions: TTC associates with acute increase in LVM, which seems to be a local effect, tending to occur in parallel with changes in concentric wall motion. MRI and TTE shows adequate consistency, primarily for the TE-method regarding LVM.
|
|
| 48. |
- Widell, Jonas, et al.
(author)
-
Interobserver variability in high-resolution CT of the lungs
- 2020
-
In: European Journal of Radiology Open. - : Elsevier. - 2352-0477. ; 7
-
Journal article (peer-reviewed)abstract
- Purpose: To quantify the interobserver variability among the most frequently encountered parenchymal patterns in High Resolution CT (HRCT) and to compare the interobserver variability in the application of the 2011 and 2018 usual interstitial pneumonia (UIP) criteria according to the joint guidelines from international thoracic and respiratory societies.Material and methods: Two observers independently evaluated 126 HRCT, with examples of most common parenchymal patterns, and noted the presence of each pattern. The readers also noted whether the findings met the 2011 criteria for UIP. In a second reading, the same readers noted whether the HRCT met the UIP criteria according to the 2018 UIP update.Results: The kappa values for interobserver variability for the different patterns ranged from 0.28 (intralobular lines) to 0.85 (tree-in-bud nodules). The kappa value for UIP pattern was similar for 2011 and 2018 criteria, 0.58 and 0.69, respectively. Compared to the 2011 UIP criteria, there was no statistically significant difference in the number of HRCT classified as UIP using the 2018 criteria.Conclusions: There is a substantial variation in interobserver agreement between the different parenchymal patterns, which suggests that some patterns a more easily identified than others. There is also a considerable reader variation in the assessment of UIP applying the 2011 UIP criteria as well as applying the 2018 UIP update.
|
|
